The US MR2 Spyder has an extremely short 5th gear (and no 6th) so its gas mileage is actually not very good on the highway. I usually got something like 36mpg.
With a 2ZZ + C60 + slightly taller tire (so about 10% lower revs, and a slightly more efficient engine), I got 42ish cruising which is pretty good IMO. These days it's hard to find a chassis in good shape for a good price, but they're still very fun cars for the money.
Since I'm no longer a penniless college student, I prefer newer cars so I don't need to constantly fix broken bits on them, and the ND Miata is a ridiculously good car even if it's not the most exciting in some ways. I'm just a little too tall for it